This invention relates to a method for treating hydrocarbonaceous fluids, such as synthetic crude oils. In another aspect, this invention relates to a method for removing contaminants, such as arsenic and selenium, from a hydrocarbonaceous fluid, such as synthetic crude oil. In still another aspect, this invention relates to a noncatalytic method for removing contaminants, such as arsenic and selenium from a hydrocarbonaceous fluid.
Recent economic and political developments have resulted in dramatic increases in the cost of energy sources such as conventional crude oil and the like. As a result of the increased prices of crude oil and as a result of real and potential shortages of crude oil, various alternative sources of energy are being investigated. It has long been known that there are many alternative sources of energy available but such sources have not been economically competitive with conventional crude oil. Now, it is apparent that the formerly noncompetitive sources of energy will be used to supply an increasing portion of our energy needs in the future. Some of the more promising sources of energy that will be used in the future include synthetic hydrocarbonaceous fluids obtained from oil shale, normally solid coal, tar (including tar sands) and the like. Often, these hydrocarbonaceous fluids are referred to under generic terms such as "synthetic crude oil," or "synthetic oil fractions."
The above-mentioned synthetic hydrocarbonaceous fluids contain contaminants that affect their ability to be readily processed into satisfactory sources of energy and precursors for the synthesis of other desired materials. For example, the above-mentioned synthetic hydrocarbonaceous fluids contain contaminants that tend to interfere with refining and chemical processes such as hydrogenation processes and in some instances they may poison or inactivate catalysts used in such processes. Particularly troublesome contaminants found in such synthetic hydrocarbonaceous fluids include arsenic and selenium contaminants. Even if the above-mentioned synthetic hydrocarbonaceous fluids are employed directly as fuels, the removal of such contaminants may be desirable from an environmental protection standpoint. Thus, it is desirable that such contaminants be removed or reduced to low concentrations in the hydrocarbonaceous fluids before they can be processed or utilized as fuels.
The prior art is replete with various methods for removing contaminants such as arsenic and selenium from hydrocarbon feedstocks. For example, U.S. Pat. No. 2,778,779 discloses a method for removing arsenic from hydrocarbon fractions by using iron, nickel and cobalt oxides as oxidizing agents to oxidize arsenic to a water soluble arsenic oxide. Thereafter, the arsenic oxide is dissolved and removed from the naturally occurring crude oil or oil fraction thereof.
Other methods for removing contaminants such as arsenic from hydrocarbon fractions include catalytic treatment methods such as those disclosed in U.S. Pat. No. 3,622,498 wherein a crude oil having a high metals content is treated in the presence of hydrogen and a slurry of a catalytic metal material to remove the contaminants therefrom.
Sophisticated treatment methods such as disclosed in U.S. Pat. No. 3,496,099 have been utilized to remove contaminants from hydrocarbon fractions by means of a hydrogen treatment method in a catalyst bed which has increasing hydrogenation catalytic activity throughout the bed. While the prior art does provide various methods for removing or reducing the contaminant levels and hydrocarbon fractions, there is still a need for more improved methods for removing contaminants such as arsenic and selenium from hydrocarbonaceous fluids.